FYI, the marrow bones are OK for them to gnaw on, but after a while they will become more brittle and might break apart like one of those pics showed…but it will take a while, like a month or more. I give my dogs nothing but knucklebones or marrowbones-RAW- and they love it and as an added bonus one of my non-B's has gotten almost of his tartar build up off, and we have only been doing the RAW diet for a month...yeah. The vet wanted him to come in for some serious teeth cleaning with doggie valium and all that...not needed anymore.
Of course I love the pics...especially the one with the funny face, second from bottom..